Method of oxidizing roofing asphalt

ABSTRACT

A method and apparatus for oxidizing roofing asphalt is disclosed in which heated liquid asphalt is subjected to air entrainment in an oxidizer tank supplied with a suitable air source, the air and asphalt mix is then mechanically mixed by an oil mill and passed through a catalyst tank so as to provide a large surface area for a relatively thin asphalt film enabling complete oxidation thereof. The resulting asphalt product is light, contains air and penetrates paper and felt much better than asphalt not so treated. Additionally, the treated asphalt covers a greater area and remains in a stable condition, thus, contributing economically to the formation of roofing shingles and the like. The apparatus includes an oxidizer tank which has horizontally positioned apertured baffles and through which the asphalt and air from a suitable source are forcibly directed, an oil mill in which a series of circular saws and spacers revolve within a housing divided into a number of attrition chambers through which the asphalt and air mixture is pumped so as to thoroughly intermix the air in the asphalt. The thoroughly mixed air and asphalt are then moved into a catalyst tank which is filled with raschig rings and which catalyst tank provides a large surface area for the thin asphalt film that forms thereover and enables the complete oxidation of the air asphalt mixture to be obtained. The asphalt product is then passed to heated storage and/or recycled if necessary and desirable.

Unite States atent [72] inventor Everett H. Crawley Lexington, Ky. [21} AppLNo. 811,518 [22] Filed Mar. 28, 1969 [45] Patented Sept. 21, 1971 [73] Assignee Volcanic Heater Inc.

Alliance, Ohio [54] METHOD OF OXIDIZING ROOFING ASPHALT 1 Claim, 4 Drawing Figs.

[52] [1.8. CI 208/6, 23/260 [51] int. Cl C10c 3/04 [50] Field of Search 208/6 [56] References Cited UNITED STATES PATENTS 2,099,434 11/1937 Culbertson 208/6 2,170,496 8/1939 Gard et al. 208/6 Primary ExaminerDelbert E. Gantz Assistant Examiner-Veronica OKeefe Attorney-Webster B. Harpman ABSTRACT: A method and apparatus for oxidizing roofing asphalt is disclosed in which heated liquid asphalt is subjected to air entrainment in an oxidizer tank supplied with a suitable air source, the air and asphalt mix is then mechanically mixed by an oil mill and passed through a catalyst tank so as to provide a large surface area for a relatively thin asphalt film enabling complete oxidation thereof. The resulting asphalt product is light, contains air and penetrates paper and felt much better than asphalt not so treated. Additionally, the treated asphalt covers a greater area and remains in a stable condition, thus, contributing economically to the formation of roofing shingles and the like.

The apparatus includes an oxidizer tank which has horizontally positioned apertured baffles and through which the asphalt and air from a suitable source are forcibly directed, an oil mill in which a series of circular saws and spacers revolve within a housing divided into a number of attrition chambers through which the asphalt and air mixture is pumped so as to thoroughly intennix the air in the asphalt. The thoroughly mixed air and asphalt are then moved into a catalyst tank which is filled with raschig rings and which catalyst tank provideS a large surface area for the thin asphalt film that forms thereover and enables the complete oxidation of the air asphalt mixture to be obtained. The asphalt product is then passed to heated storage and/or recycled if necessary and desirable.

I RECYCLE LINE l COMIZFIIESSED 2 37 VALVE r-a sou jg M14 IO 3 24 ST$EIQEE oxn- STORAGE DIZER 36 PUMP OIL MILL v.

315 500"; b a v HEATER [2 HEATER HEATER II 23 PATENTEDSEP21 15m 3 6 07,715

RECYCLE LINE H ''Z'? 7 VALVE r1 SOURCE r1 STORAGE TANK I STORAGE PUMP i6 HEATER l2 E ER ENTOR. EVERETT H. CRAWLEY FIG. 3 WW ATTORNEY METHOD OF OXIDIZING ROOFING ASPHALT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method for oxidizing roofing asphalt to produce an improved asphalt product that has a greater penetrating ability and greater spreadablility than asphalt heretofore known in the art.

2. Description of the Prior Art Asphalt used in roofing applications in the past has been subjected to oxidation attempts by bubbling air under pressure through a quantity of heated asphalt. Some oxidation has been obtained by this method and the asphalt so treated has a known penetration ability at a specified softening point which requires a known quantity of asphalt to form roofing products. The present invention results in a a greatly improved asphalt which is particularly adapted for the manufacture of roofing materials including shingles and roll-roofing products and the like as the asphalt produced by the subject method has a much higher penetrating ability at a fixed flowing temperature and it is cable of covering a greater area and remaining in a stable condition. Thus, considerably more of a specific roofing product may be formed with a lesser quantity of the asphalt oxidized by the method herein disclosed than has heretofore been believed possible.

SUMMARY OF THE INVENTION The method of and apparatus for oxidizing roofing asphalt disclosed herein acts to insure complete oxidation of an asphalt which is preheated by running the same and air from a suitable source through an oxidizer tank for an initial mixing and subsequently through an oil mill for mechanically mixing and introducing the air into the asphalt and breaking down the asphalt into a very fine solution and subsequently, moving the asphalt and air mixture into a catalyst tank containing raschig rings which provide an extremely large surface area over which the air and asphalt mixture can form a thin film which consists greatly in completing the oxidation. The resultant product is light, contains a large quantity of air and penetrates roofing materials to a much greater extent and provides a greater covering ability.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of the apparatus for practicing the method disclosed herein.

FIG. 2 is an enlarged cross-sectional detail of an oxidizer tank seen in FIG. 1.

FIG. 3 is an enlarged cross-sectional detail of an oil mill seen in FIG. 1.

FIG. 4 is a cross-sectional detail of a catalyst tank seen in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The method and apparatus for oxidizing roofing asphalt to improve its penetrating characteristics and covering ability is best described by referring to the illustration of FIG. 1 of the drawing wherein the storage tank comprises a source of roofing asphalt and incorporates a heater 11 so that the asphalt in the tank may be maintained at a temperature between 375 F. and 500 F. A pump 12 moves the heater asphalt from the tank 10 to the upper portion of an oxidizer tank 13.

By referring to FIG. 2 of the drawings, it will be seen that the oxidizer tank 13 has an air inlet 14 in its top portion 15 and an asphalt inlet 16 adjacent thereto. The interior of the oxidizer tank 13 includes vertically spaced apertured bafile plates 17 intermixed with baffles 18 having single openings therethrough and centrally of the assembly a single central disc 19 is provided to insure the flow of the asphalt and air downwardly through the oxidizer tank 13 in a tortuous path to facilitate intermixing of the air and asphalt. The mixed product leaves by an outlet 20.

Again referring to FIG. 1 it will be seen that compressed air from a compressed air source 21 and controlled by valve 22 communicates with the air inlet 14 of the oxidizer tank 13. The product leaving the outlet 20 of the oxidizer tank 13 enters an inlet 23 of oil mill 24 which has a heater 25 therein.

By referring to FIG. 3 of the drawings, it will be seen that the oil mill 24 incorporates a series of circular saws 26 alternated with spacers 27 on a horizontal shaft 28 which is revolved by a source of rotary motion not shown. The saws and spacers revolve within the housing of the oil mill 24 which is divided into a number of attrition chambers 29 through which the asphalt and air mixture is pumped from the inlet 23 to an inlet 30. The action of the oil mill results in a mechanical mixing of the air and asphalt which could not otherwise be achieved. The air and asphalt mixture then moves to a catalyst tank 31. I

By referring to FIG. 4 of the drawings, it will be seen that this tank encloses a slightly smaller perforated basket 32 which is filled with raschig rings 33 which are ceramic tubes usually a half-inch in diameter and approximately an inch in length. The asphalt and air mixture is thus provided with an extremely large surface area so that a thin asphalt and air film exists over the surfaces of the raschig rings and enables a complete oxidation of the asphalt to take place.

By referring again to FIG. 1 it will be seen that the asphalt mixture enters the catalyst tank 31 by way of an inlet 34 and leaves by way of an outlet 35 and flows to a heated storage tank 36 which also communicates with the storage tank 10 by a valved recycling line 37.

It will thus be seen that the asphalt from the storage tank 10 in a heated condition flows through the apparatus including the oxidizer 13, the oil mill 24, the catalyst tank 31 and into the heated storage tank 36 and it will be appreciated by those skilled in the art that recycling of the air asphalt may be employed if desired although it has been found that the apparatus as disclosed enables the carrying out of the method disclosed herein which results in a vastly improved roofing asphalt material and particularly with respect to achieving higher penetrations at any softening point and an increased covering ability. The method provides fast, in-line oxidizing in asphalt refineries as from the bottoms of the tower or flasher units of the refinery and the method gives improved properties to lower grade asphalt.

The method produces excellent dead level roofing and similar industrial asphalts including those used for joining compounds etc. Asphalt produced by the method makes a good lower melting point asphalt such as paving grades and emulsion base asphalts.

Those skilled in the art will observe that by changing base asphalts, temperatures, air ratios and residence time, many grades of asphalt may be made on stream, efficiently and at low cost.

Although but one embodiment of the present invention has been illustrated and described it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.

lclaim:

l. The method of oxidizing asphalt which includes initially heating the asphalt to a temperature in the range of 375F. to 500F. to soften and substantially fluidize the asphalt, moving the fluid asphalt through an oxidizer to which air is introduced under pressure so as to mix the air and asphalt, moving the air and asphalt mixture to and through a mechanical mill and milling the air and asphalt mixture so as to finely divide and mix the asphalt and air in a solution, moving the air and asphalt mixture to a catalyst tank containing raschig rings, spreading the air and asphalt mixture in a fine film over the rachig rings in the catalyst tank, retaining the air and asphalt mixture in said catalyst tank until substantially complete oxidation of the asphalt occurs, and subsequently moving the oxidized asphalt to a heated storage tank. 

